[vlc-devel] [PATCH 1/1] Supporting ONVIF PRofile-G recording playback

David R. Robison david.robison at openroadsconsulting.com
Wed Aug 6 15:45:38 CEST 2014

OK, so what if I create a new media_player function called 
libvlc_media_player_set_time_base and create an input variable called 
"time-base". This value would normally be zero, which would cause all 
the existing code to work as is. In the case of live555 this will cause 
the "Range: ntp" header to be sent. However, if the value is non-zero, 
it will be interpreted as the absolute date/time (in Unix seconds) of 
the start of the presentation. Then the set_time and set_length will 
work the same but the "time" will be an offset from the "time-base". For 
the live555, this will cause the "Range: clock" header to be sent. It 
also means that the get_time calls will continue to work, returning the 
time offset from the "time-base". This will mean a new input variable 
called "time-base" and new DEMUX_SET_TIME_BASE and 
INPUT_CONTROL_SET_TIME_BASE control cases. Does this sound reasonable 
and better then my previous approach?

David R Robison
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On 8/5/2014 8:11 AM, Rémi Denis-Courmont wrote:
> Le 2014-08-05 14:20, David R. Robison a écrit :
>> Thanks for the clarification, however, I still need to be able to
>> determine which sendPlayCommand signature to use. ONVIF requires the
>> "range: clock" header element rather than the "range: ntp" element.
>> One approach would be to determine if the "time" is being sent is in
>> absolute date/time (unix seconds). I could test the "time" variable
>> and if it is greater than 24*60*60 seconds then assume absolute time
>> is being sent and use the sendPlayCommand with the ISO 8601 formatted
>> times otherwise use the sendPlayCommand with doubles. This is a bit of
>> a kluge but may mean minimal changes to VLC. Any thoughts.
> If DEMUX_GET_TIME returns time with the same base, then there is no 
> need to define a new way to set time. You only need a way to select 
> the time base.

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